A motion planning method for spacecraft attitude maneuvers using single polynomials

A motion planning technique for generating smooth attitude slew maneuvers is presented, which can generate suboptimal feasible trajectories with low computational cost in the presence of constraints. The attitude coordinates are shaped by time-dependent polynomials, whose coefficients are determined by matching prescribed arbitrary boundary conditions. Quaternions are used as the reference attitude parametrization for arbitrary maneuvers, which require normalization of the four independently shaped coordinates. In the case of spin-to-spin maneuvers, a particular combination of Euler Angles are used. The torque profile is evaluated using inverse dynamics, which allows the feasibility of the maneuver given the actuator constraints to be checked. With this approach, a root-finding method is used to select the minimum time for a certain path. By increasing the degree of the polynomial free coefficients are introduced, thus pointing constraints can be accommodated and time can be optimized amongst this class of motion. This motion planning method is applied to a flexible spacecraft model, demonstrating its effectiveness at reducing spillover vibrations.